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Mihailescu M, Worcester DL, Carroll CL, Chamberlin AR, White SH. DOTAP: Structure, hydration, and the counterion effect. Biophys J 2023; 122:1086-1093. [PMID: 36703558 PMCID: PMC10111261 DOI: 10.1016/j.bpj.2023.01.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/04/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
The cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) is one of the original synthetic cationic lipids used for the liposomal transfection of oligonucleotides in gene therapy. The key structural element of DOTAP is its quaternary ammonium headgroup that is responsible for interactions with both nucleic acids and target cell membranes. Because these interactions are fundamental to the design of a major class of transfection lipids, it is important to understand the structure of DOTAP and how it interacts with halide counterions. Here, we use x-ray and neutron diffraction techniques to examine the structure of DOTAP and how chloride (Cl-) and iodide (I-) counterions alter the hydration properties of the DOTAP headgroup. A problem of particular interest is the poor solubility of DOTAP/I- in water solutions. Our results show that the poor solubility results from very tight binding of the I- counterion to the headgroup and the consequent expulsion of water. The structural principles we report here are important for assessing the suitability of DOTAP and its quaternary ammonium derivatives for transfection.
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Affiliation(s)
- Mihaela Mihailescu
- Institute for Bioscience and Biotechnology Research, Rockville, Maryland.
| | - David L Worcester
- Biology Division, University of Missouri, Columbia, Missouri; NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland; Department of Physiology and Biophysics, University of California at Irvine, Irvine, California
| | | | - A Richard Chamberlin
- Department of Chemistry, University of California at Irvine, Irvine, California; Department of Pharmaceutical Sciences, University of California at Irvine, Irvine, California
| | - Stephen H White
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland; Department of Physiology and Biophysics, University of California at Irvine, Irvine, California
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2
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Martins LS, Nomura DA, Duarte EL, Riske KA, Lamy MT, Rozenfeld JHK. Structural characterization of cationic DODAB bilayers containing C24:1 β-glucosylceramide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:643-650. [PMID: 30611744 DOI: 10.1016/j.bbamem.2018.12.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/09/2018] [Accepted: 12/28/2018] [Indexed: 01/13/2023]
Abstract
The effect of 5 mol%, 9 mol%, and 16 mol% of C24:1 β-glucosylceramide (βGlcCer) on the structure of cationic DODAB bilayers was investigated by means of differential scanning calorimetry (DSC), electron spin resonance (ESR) spectroscopy and fluorescence microscopy. βGlcCer is completely miscible with DODAB at all fractions tested, since no domains were observed in fluorescence microscopy or ESR spectra. The latter showed that βGlcCer destabilized the gel phase of DODAB bilayers by decreasing the gel phase packing. As a consequence, βGlcCer induced a decrease in the phase transition temperature and cooperativity of DODAB bilayers, as seen in DSC thermograms. ESR spectra also showed that βGlcCer induced an increase in DODAB fluid phase order and/or rigidity. Despite their different structures, a similar effect of loosening the gel phase packing and turning the fluid phase more rigid/organized has also been observed when low molar fractions of cholesterol were incorporated in DODAB bilayers. The structural characterization of mixed membranes made of cationic lipids and glucosylceramides may be important for developing novel immunotherapeutic tools such as vaccine adjuvants.
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Affiliation(s)
- Letícia S Martins
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil
| | - Daniela A Nomura
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Karin A Riske
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, CP 66318, CEP 05315-970 São Paulo, SP, Brazil
| | - Julio H K Rozenfeld
- Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862, 04023-062 São Paulo, SP, Brazil.
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De Neve L, Vermeir L, Sabatino P, Saveyn P, Denon Q, Martins J, Van der Meeren P. Quantification of counterion binding to and its effects on aqueous dispersions of dialkyl cationic surfactants. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2017.04.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Pöyry S, Vattulainen I. Role of charged lipids in membrane structures - Insight given by simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2322-2333. [PMID: 27003126 DOI: 10.1016/j.bbamem.2016.03.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/09/2016] [Accepted: 03/11/2016] [Indexed: 01/28/2023]
Abstract
Lipids and proteins are the main components of cell membranes. It is becoming increasingly clear that lipids, in addition to providing an environment for proteins to work in, are in many cases also able to modulate the structure and function of those proteins. Particularly charged lipids such as phosphatidylinositols and phosphatidylserines are involved in several examples of such effects. Molecular dynamics simulations have proved an invaluable tool in exploring these aspects. This so-called computational microscope can provide both complementing explanations for the experimental results and guide experiments to fruitful directions. In this paper, we review studies that have utilized molecular dynamics simulations to unravel the roles of charged lipids in membrane structures. We focus on lipids as active constituents of the membranes, affecting both general membrane properties as well as non-lipid membrane components, mainly proteins. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Sanja Pöyry
- Department of Physics, Tampere University of Technology, POB 692, FI-33101 Tampere, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, POB 692, FI-33101 Tampere, Finland; MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark; Department of Physics, University of Helsinki, POB 64, FI-00014 Helsinki, Finland.
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Kepczynski M, Róg T. Functionalized lipids and surfactants for specific applications. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2362-2379. [PMID: 26946243 DOI: 10.1016/j.bbamem.2016.02.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Synthetic lipids and surfactants that do not exist in biological systems have been used for the last few decades in both basic and applied science. The most notable applications for synthetic lipids and surfactants are drug delivery, gene transfection, as reporting molecules, and as support for structural lipid biology. In this review, we describe the potential of the synergistic combination of computational and experimental methodologies to study the behavior of synthetic lipids and surfactants embedded in lipid membranes and liposomes. We focused on select cases in which molecular dynamics simulations were used to complement experimental studies aiming to understand the structure and properties of new compounds at the atomistic level. We also describe cases in which molecular dynamics simulations were used to design new synthetic lipids and surfactants, as well as emerging fields for the application of these compounds. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Mariusz Kepczynski
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
| | - Tomasz Róg
- Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101, Tampere, Finland; Department of Physics, Helsinki University, P.O. Box 64, FI 00014 Helsinki, Finland.
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Roy S, Gruenbaum SM, Skinner JL. Theoretical vibrational sum-frequency generation spectroscopy of water near lipid and surfactant monolayer interfaces. J Chem Phys 2014; 141:18C502. [DOI: 10.1063/1.4895546] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- S. Roy
- Theoretical Chemistry Institute and Department of Chemistry, 1101 University Ave., University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S. M. Gruenbaum
- Theoretical Chemistry Institute and Department of Chemistry, 1101 University Ave., University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J. L. Skinner
- Theoretical Chemistry Institute and Department of Chemistry, 1101 University Ave., University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Disalvo EA, Frias MA. Water state and carbonyl distribution populations in confined regions of lipid bilayers observed by FTIR spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:6969-6974. [PMID: 23293989 DOI: 10.1021/la304390r] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
It has been suggested that water in confined regions presents different properties than bulk water, mainly because of the changes in water population species that may be induced by the adjacent walls of different polarities in terms of hydrogen bond formation. In this context, it would be expected that lipids in the gel and the fluid states should offer different templates for water organization. The presence of water pockets or defects in lipid bilayers has been proposed to explain the insertion of charged and polar peptides and amino acids in membranes. In this work, we provide direct evidence by means of FTIR spectroscopy that water band profiles are changed whether lipids are in the solid state, in the gel state after heating and cooling across the phase transition, or in the fluid state. The different bands found in each case were assigned to different H-bonded water populations in agreement with the exposure of carbonyl groups.
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Affiliation(s)
- E A Disalvo
- Laboratory of Biointerphases and Biomimetics Systems, CITSE (Universidad Nacional de Santiago del Estero, and CONICET), Santiago del Estero, Argentina.
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Disalvo EA, Bouchet AM, Frias MA. Connected and isolated CH2 populations in acyl chains and its relation to pockets of confined water in lipid membranes as observed by FTIR spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1683-9. [PMID: 23500348 DOI: 10.1016/j.bbamem.2013.02.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 01/15/2013] [Accepted: 02/13/2013] [Indexed: 11/18/2022]
Abstract
Analysis of the band corresponding to the frequency of vibrational symmetric stretching mode of methylene groups in the lipid acyl chains and the bands of water below and above the phase transition of different lipids by Fourier transform infrared spectroscopy gives strong support to the formation of confined water pockets in between the lipid acyl chains. Our measures and analysis consolidate the mechanism early proposed by Traüble, in the sense that water is present in kinks formed by trans-gauche isomers along the hydrocarbon tails. The formation of these regions depends on the acyl lipid composition, which determines the presence of different populations of water species, characterized by its degree of H bond coordination in fluid saturated or unsaturated lipids. The free energy excess due to the reinforcement of the water structure along few water molecules in the adjacencies of exposed membrane residues near the phase transition is a reasonable base to explain the insertion and translocation of polar peptides and amino acid residues through the biomembrane on thermodynamic and structural grounds.
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Affiliation(s)
- E A Disalvo
- Universidad Nacional de Santiago del Estero, Santiago del Estero, Argentina.
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Pokorna S, Jurkiewicz P, Cwiklik L, Vazdar M, Hof M. Interactions of monovalent salts with cationic lipid bilayers. Faraday Discuss 2013; 160:341-58; discussion 389-403. [DOI: 10.1039/c2fd20098h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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